In general, a motor is an instrument for converting an electric energy to a kinetic energy. There are two types of motors: one is a rotary motor which converts the electric energy to a rotational movement, and the other is a reciprocating motor which converts the electric energy to a linear reciprocal movement.
As a driving source, the motor is adopted for use to various fields. Especially, it is installed in almost every home appliance such as a refrigerator, an air-conditioner, a washing machine or an electric fan.
In case of the refrigerator and the air-conditioner, the motor is not only used to rotate a ventilating fan but also installed as a driving source at a compressor of a cooling cycle apparatus of the refrigerator and the air-conditioner.
FIG. 1 is an example of a general reciprocating motor in accordance with a conventional art.
As shown in FIG. 1, the reciprocating motor includes a stator having a cylindrical outer core 10 and an inner core 20 inserted into the outer core 10 with a predetermined space, a winding coil 30 combined to the outer core 10 or the inner core 20, and a mover 40 inserted linearly movable between the outer core 10 and the inner core 20.
FIG. 1 shows the structure in which the winding coil 30 is combined with the outer core 10.
The outer core 10 is formed as a cylindrical stacked body in which channel-shaped thin lamination sheets 11 are stacked radially to make a cylindrical form.
The channel portion of the lamination sheet 11 makes a pass part 11a where a flux flows, and both ends make pole parts 11b where a pole is formed. The space with one side opened formed inside the pass part 11a makes an opening 11c in which the winding coil 30 is positioned.
Referring to the winding coil 30, a coil is wound for a plurality of times to form a ring shape, a section form of which is equivalent to the form of the opening 11c. 
A thin insulation coating film 31 is formed on the outer surface of the winding coil 30.
The inner core 20 is formed as a cylindrical stacked body that a thin rectangular lamination sheet 21 having a length equivalent to the length of the outer core 10 is stacked radially to make a cylindrical form.
The mover 40 includes a cylindrical magnet holder 41 inserted between the outer core 10 and the inner core 20 and a plurality of permanent magnets 2 fixedly combined to the outer circumferential surface of the magnet holder 41.
The length Lp of the permanent magnet 42 is usually equivalent to the sum of the length Lp of the pole part and the interpole distance Lb. Accordingly, since the length of the permanent magnet 42 is in proportion to the interpole distance Lb positioned at both sides of the opening 11c, the shorter the interpole distance Lb is, the shorter Lm of the permanent magnet 42 becomes.
The length Lp of the pole part corresponds to the stroke, and the interpole distance Lb is equivalent to the width of the entrance of the opening 11c. 
As for the combination between the winding coil 30 and the outer coil 10, the insulation coating film 31 is coated at the outer side of the winding coil 30 formed as a coil is wound in a ring-shape for many of times, and the lamination sheets 11 constituting the outer core 10 are stacked to be combined radially at the winding coil 30.
The lamination sheets 11 are stacked such that the winding coil 30 is inserted into the opening 11c. 
The operation of the reciprocating motor constructed as described above will now be explained with reference to FIG. 2.
As shown in FIG. 2, when a current flows to the winding coil 30, a flux is generated around the winding coil 30 due to the current flowing along the winding coil 30. The flux flows to form a closed loop along the pass part 11a of the outer core and the inner core 20 which constitute the stator (S).
The interaction between the flux according to the current flowing along the coil 30 and the flux according to the permanent magnet 42 constructing the mover 40 makes the permanent magnet 42 to move in the axial direction.
When the direction of the current flowing to the winding coil 30 is changed, the direction of the flux formed at the pass part 12 of the outer core and the inner core 20 is accordingly changed, and thus, the permanent magnet 42 is moved in the opposite direction.
When the current is supplied to the permanent magnet 42 by changing its direction by turns, the permanent magnet 42 is moved linearly and reciprocally between the outer core 10 and the inner core 20. Accordingly, the mover 40 has a linear reciprocal driving force.
However, the reciprocating motor having the above described construction has many problems.
For example, first, since the width of the entrance of the opening 11c where the winding coil 30 is positioned, that is, the interpole distance Lb, is great, causing that the size of the high-priced permanent magnet 42 which is determined depending on the interpole distance Lb is lengthened. Thus, as the amount of the permanent magnet 42 to be used is increased, a high production cost is incurred which is not suitable to a mass-production.
Secondly, since the outer core 10 is constructed by stacking the plurality of lamination sheets 11 at the winding coil 30 after the winding coil 30, which is formed by winding the coil having a predetermined length many times, is coated for insulation, it is not easy to fabricate the winding coil 30 in conformity to the form of the opening 11c of the outer core 10.
In addition, since the winding coil 30 is easily deformed, making it difficult to stack the lamination sheets 11, the fabrication time is much taken and more processes are required, and thus, it is not suitable to a mass-production.